Polar Ice Caps

A polar ice cap is a high-altitude area that is covered by ice. There are no requirements to be considered a polar ice cap beyond the region being at a planet geographic pole. It does not matter if the polar ice cap covers land or water.

A polar ice cap is not, however, actually an ice cap. Ice caps are dome-shaped masses of glacier ice that are less than 12 million acres and must be over land. Anything larger than that and it is an ice sheet, which is what covers nearly all of Antarctica.

The Earth’s polar ice caps are composed of water ice. As a result, both of them, but particularly the polar ice cap at the North Pole, have become central sites in demonstrating the dangers of climate change. This includes concerns over rising sea levels, the loss of animal habitats and the potential release of methane into the atmosphere.

Arctic sea ice always grows and shrinks with the seasons, but thanks to global warming, it's been doing a lot more of the latter lately. Here's a graphical look at just how quickly this sea change is happening.